IkappaBbeta interacts with the retinoid X receptor and inhibits retinoid-dependent transactivation in lipopolysaccharide-treated cells.
To elucidate the molecular action of the NFkappaB inhibitor IkappaBbeta, we isolated a number of IkappaBbeta interactors using the yeast two-hybrid system. These include the retinoid X receptor (RXR), whose interaction with IkappaBbeta is significantly stimulated by the RXR ligand 9-cis-retinoic acid, as shown in the yeast system as well as the glutathione S-transferase pull down assays. RXR is a nuclear protein, whereas IkappaBbeta accumulates in the nucleus only in cells stimulated with lipopolysaccharide or other inducers that result in prolonged activation of NFkappaB. Consistent with this, cotransfection with IkappaBbeta specifically repressed the 9-cis-RA-induced transcriptional activities of RXR in an lipopolysaccharide-dependent manner. These results suggest a novel IkappaBbeta-mediated antagonism between the signaling pathways of NFkappaB and RXR.
Na
S Y
SY
Department of Biology, Chonnam National University, Kwangju, 500-757 Korea.
Kim
H J
HJ
Lee
S K
SK
Choi
H S
HS
Na
D S
DS
Lee
M O
MO
Chung
M
M
Moore
D D
DD
Lee
J W
JW
D000077556:Alitretinoin; D000818:Animals; D002460:Cell Line; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004268:DNA-Binding Proteins / Q000378:metabolism*; D020672:I-kappa B Proteins; D008070:Lipopolysaccharides / Q000494:pharmacology*; D051379:Mice; D000072000:NF-KappaB Inhibitor alpha; D011485:Protein Binding; D018168:Receptors, Retinoic Acid / Q000819:agonists / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D047488:Retinoid X Receptors; D015398:Signal Transduction; D014157:Transcription Factors / Q000819:agonists / Q000378:metabolism*; D015533:Transcriptional Activation / Q000187:drug effects; D014162:Transfection; D014212:Tretinoin / Q000494:pharmacology
D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D008070:Lipopolysaccharides; C000606205:Nfkbia protein, mouse; D018168:Receptors, Retinoic Acid; D011994:Recombinant Proteins; D047488:Retinoid X Receptors; D014157:Transcription Factors; D000072000:NF-KappaB Inhibitor alpha; D000077556:Alitretinoin; D014212:Tretinoin